Obama, who made the comment aboard Air Force One while watching a Miami Dolphins-Carolina Panthers game, also said players are aware of the risks.

"At this point, there's a little bit of caveat emptor," Obama told The New Yorker's David Remnick. "These guys, they know what they're doing. They know what they're buying into. It is no longer a secret. It's sort of the feeling I have about smokers, you know?"

Obama. who has two daughters, has expressed concern before about concussions and the other physical dangers of football, especially at the professional level.

The president will likely be asked about it again if - as expected - he grants the tradition presidential interview on Super Bowl Sunday, Feb. 2.